A Hall sensor is a transducer that varies its output voltage in response to a measured magnetic field. In its simplest form, the Hall sensor operates as an analogue transducer, directly returning a voltage for the measured field.
Electricity carried through a conductor will produce a magnetic field that varies with current, and a Hall sensor measures the current without interrupting the circuit.
Hall sensors are typically used in industrial applications such as pneumatic cylinders, or in consumer equipment such as computer printers or keyboards.
Hall sensors are also commonly used to time the speed of wheels and shafts, such as for internal combustion engine ignition timing, tachometers and anti-lock braking systems. They are used in brushless DC electric motors to detect the position of the permanent magnet.